In order to decorate an element or component of a timepiece or piece of jewelry, a hot enameling technique may be used, particularly after a set of cells or partitions has been created on the element or on the component. This conventional technique known as “cloisonné” is one of numerous enameling techniques, which include amongst others: “grisaille”, dry applique, painting on enamel, “champlevé”, “basse-taille”, “plique-á-jour”, relief enameling, “paillonné”, to name the main techniques. The principle of this traditional decorative technique consists in manually creating a design formed of metal wire partitions, then filling the partition walls with successive layers of transparent or opaque enamels on a metal or ceramic support. The raw materials of the vitreous substance known as enamel are mainly silica, in the form of very pure sand, feldspars, pegmatites, chalk, lime and sometimes kaolin, associated with metal compounds to give the enamel its colour. This substance deposited on a surface of a component is fired until it fuses and adheres to the metal or ceramic component. The process of creating the decoration by various manual steps is long and cannot be reproduced in an identical manner from one component to the next, which is a drawback.
In the case of the “cloisonné” or partitioned technique, there are generally at least nine steps required to create the decorated element. In a first step, a drawing of the pattern must be created directly on paper or on a computer with life-size printing of the drawing. In a second step, the patterns of the decoration are produced by hand by means of a metal wire on the drawing used as a base. In a third step, the drawing is reproduced on a metal or ceramic support, notably by hand engraving, machine engraving or free hand engraving. In a fourth step, the metal or ceramic support is enamelled with a first layer of transparent enamel. In a fifth step, the patterns of the decoration are placed on the enamelled ceramic or metal support to form the “cloisonné” or partitioned patterns. In a sixth step, the decoration patterns are glued to the metal or ceramic support to hold the partitions. In a sixth complementary step, the decoration patterns secured to the ceramic or metal support are leveled. The seventh step consists in firing the enamelled support with the glued partitions, in order to trap them in the enamel as it fuses to obtain solid and hardened partitions. In the eighth step, the enameling operation is performed in several placing and firing phases. The ninth step consists of stoning and polishing the enamelled part. This constitutes a very large number of steps for such a method of producing a decorated element, which is a drawback.
It is also to be noted that there several problems remain as regards the aforementioned technique for producing a decorated element. These problems are, on the one hand, the manual production of the decorations, and the geometry, placing and hold thereof. The decorations are metal wires or metal strips bent into simple geometric shapes. The wires or strips are held together by adhesive bonding, which has the drawback of being neither rigid nor impermeable.
CH Patent Application No 707 533 A2 describes a method for manufacturing a watch dial decorated with embroidery. First of all, a decal etch is made in a cloth canvas or embroidery. Once the overlay or copy sheet is pierced with the desired design, a powder is spread over the overlay. The design is then printed on the canvas to reveal the design for the embroidery operation, which follows this printing step. Once the embroidery is finished, the decorated canvas is bonded to a support, such as a watch dial. This method also includes a very large number of steps for decorating the watch dial, which is a drawback. Further, it is not possible to produce a decoration of complex shape with this method.
EP Patent Application No. 2 316 299 A1 describes a timepiece or piece of jewelry and the method of fabricating the same. The piece includes a metal base structure, which is provided with a relief decoration, and with an elastomer layer deposited on a surface of the structure by means of an adhesion layer. The decorative design is obtained by milling or chemical etching or laser or stamping, but it cannot produce a sufficiently precise decoration of complex shape, which is a drawback.
EP Patent Application No. 2 806 315 A2 describes the creation of a watch component, such as a coloured dial or display. To achieve this, an opaque silicon wafer is used as the base on which a first thin film of silicon nitride is deposited. A photosensitive resin mask is arranged on the first film for a photolithography operation. Illuminated portions of the resin are removed and the first film is etched. Thereafter, a metal or ceramic layer is deposited. However, it is difficult to obtain a decoration that is sufficiently precise and of complex shape, which is a drawback.